Three‐dimensional antidunes coexisting with alternate bars,Earth Surface Processes and Landforms

当前位置： X-MOL 学术 › Earth Surf.Process. Land. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Three‐dimensional antidunes coexisting with alternate bars
Earth Surface Processes and Landforms ( IF 2.8 ) Pub Date : 2020-06-26 , DOI: 10.1002/esp.4938
Takuya Inoue ₁ , Yasunori Watanabe ₂ , Toshiki Iwasaki ₂ , Junichi Otsuka ₁

Affiliation

Antidunes are fluvial bedforms that form in rivers with supercritical flows. The water surface over antidunes is strongly in phase with the bed surface, and the water surface is amplified to produce large surface waves. Many experimental studies have addressed antidunes; however, the shapes of three‐dimensional antidunes in a wide channel with alternate bars have not yet been appropriately understood. In this study, we experimentally investigated the streamwise and transverse length scales of antidunes under conditions with a large width–depth ratio. Our experimental results provide evidence for the coevolution of antidunes and free alternate bars, and show for the first time that the development of free bars greatly alters the three‐dimensional shape of water surface waves over antidunes. In the absence of free bars in a wide channel, multiple longitudinal wave trains form, and the number of wave trains counted in the transverse direction increases with increases in the width–depth ratio. However, the presence of free bars affects the local flow characteristics, resulting in a decrease of the number of wave trains in the transverse direction. Therefore, we propose a simple model for predicting the reduction in the number of wave trains by combining two previous theories for antidunes and free bars. Results obtained by the model were found to largely agree with experimental observations. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd

中文翻译：

与替代条共存的三维反沙丘

反沙丘是河流中形成的具有超临界水流的河床形式。反沙丘上的水表面与床层表面高度同相，水表面被放大以产生大的表面波。许多实验研究都针对抗沙丘。但是，在宽通道中具有交替条形的三维反沙丘的形状尚未得到适当的理解。在这项研究中，我们通过实验研究了宽宽比大的条件下，反沙丘的水流和横向长度尺度。我们的实验结果为反沙丘和自由替代条的共同进化提供了证据，并首次表明自由条的发展极大地改变了反沙丘上水面波的三维形状。在没有免费频道的情况下，形成多个纵向波列，并且沿横向计数的波列数目随着宽度-深度比的增加而增加。但是，自由棒的存在会影响局部流动特性，从而导致沿横向方向的波列数量减少。因此，我们提出了一个简单的模型，通过结合反沙丘和自由条的两个先前理论来预测波列数量的减少。发现该模型获得的结果与实验观察结果基本吻合。©2020作者。约翰·威利父子有限公司出版的《地球表面过程和地形》自由棒的存在会影响局部流动特性，从而导致横向波列数量的减少。因此，我们提出了一个简单的模型，通过结合反沙丘和自由条的两个先前理论来预测波列数量的减少。发现该模型获得的结果与实验观察结果基本吻合。©2020作者。约翰·威利父子有限公司出版的《地球表面过程和地形》自由棒的存在会影响局部流动特性，从而导致横向波列数量的减少。因此，我们提出了一个简单的模型，通过结合反沙丘和自由条的两个先前理论来预测波列数量的减少。发现该模型获得的结果与实验观察结果基本吻合。©2020作者。约翰·威利父子有限公司出版的《地球表面过程和地形》©2020作者。约翰·威利父子有限公司出版的《地球表面过程和地形》©2020作者。约翰·威利父子有限公司出版的《地球表面过程和地形》

更新日期：2020-06-26

点击分享查看原文

点击收藏

公开下载

阅读更多本刊最新论文本刊介绍/投稿指南11